Mid Air Collision/ Brazil Crash
07-24-2008, 12:39 PM
#11
On Reserve
Joined APC: Feb 2008
Position: CAL B757-767 Captain
Posts: 24
You can set the FMC to fly an offset to either side of the airway. In the north atlantic and WATRS it is called SLOP, Strategic Lateral Offset Procedures. It might be a good procedure in South America as well.
07-24-2008, 12:40 PM
#12
Gets Weekends Off
Joined APC: Jun 2007
Position: Legacy FO
Posts: 4,105
I travel a lot and have recently developed fear of flying. It might take just 5 minutes of any exp ATC’s/Pilot busy time to answer them but it will be really very helpful for me:
a) Brazil crash happened because transponder for one of the aircraft was accidentally turned off by pilot. I think ATC’s will be aware if a transponder was turned off in an aircraft immediately as there will be some changes in the display on your screen. What was surprising was that ATC’s in Brazil didn’t try to contact the flight for 50 minutes even after being aware of the malfunctioning.
In case transponder is turned off (or both transponder malfunction) does ATC’s immediately try to contact the aircraft. What if they are not able to contact the flight? Do they religiously try again and again to contact the flight?
b) In the Brazil’s ATC screen there were two altitudes shown. One was mode C altitude and the other one flight plan. The flight plan showed FL360 to be maintained but the flight was cleared to fly at Fl370. Once the transponder was off the mode C altitude reading was gone and the display showed FL360 as it was the flight level. For 50 minutes ATC didn’t contact the flight as it thought the aircraft was flying at FL360. Also once mode C reading was off, primary radar kicked in to replace the reading. However primary radar reading as per to report attached was unreliable and had an error of 4000 Ft. Also that reading sometime showed Fl360 instead of correct FL370. Eventually both flight collided.
· Does primary radar give correct data in India and western countries. I hear most of the time the radar is malfunctioning.
· Once the mode C altitude is not shown, how do they reckon the correct altitude? Is it flight plan level (because it can be changed), or cleared flight level (it can be mistakenly wrongly entered or the aircraft might not be following it), or do they take the words of pilot for the height (after u contact him immediately once his transponder is off).
· If somehow the transponder is off and critical flight data is not coming correct for pilot the only way to land safely is primary radar assistance from ATC. Is primary radar accurate and reliable?
· How is the instrument in Indian ATC? Are they outdated or as per to western standards.
I will be really very very thankful if anyone of you can take just 5 minutes and somehow let me allay the fear of flying.
a) Brazil crash happened because transponder for one of the aircraft was accidentally turned off by pilot. I think ATC’s will be aware if a transponder was turned off in an aircraft immediately as there will be some changes in the display on your screen. What was surprising was that ATC’s in Brazil didn’t try to contact the flight for 50 minutes even after being aware of the malfunctioning.
In case transponder is turned off (or both transponder malfunction) does ATC’s immediately try to contact the aircraft. What if they are not able to contact the flight? Do they religiously try again and again to contact the flight?
b) In the Brazil’s ATC screen there were two altitudes shown. One was mode C altitude and the other one flight plan. The flight plan showed FL360 to be maintained but the flight was cleared to fly at Fl370. Once the transponder was off the mode C altitude reading was gone and the display showed FL360 as it was the flight level. For 50 minutes ATC didn’t contact the flight as it thought the aircraft was flying at FL360. Also once mode C reading was off, primary radar kicked in to replace the reading. However primary radar reading as per to report attached was unreliable and had an error of 4000 Ft. Also that reading sometime showed Fl360 instead of correct FL370. Eventually both flight collided.
· Does primary radar give correct data in India and western countries. I hear most of the time the radar is malfunctioning.
· Once the mode C altitude is not shown, how do they reckon the correct altitude? Is it flight plan level (because it can be changed), or cleared flight level (it can be mistakenly wrongly entered or the aircraft might not be following it), or do they take the words of pilot for the height (after u contact him immediately once his transponder is off).
· If somehow the transponder is off and critical flight data is not coming correct for pilot the only way to land safely is primary radar assistance from ATC. Is primary radar accurate and reliable?
· How is the instrument in Indian ATC? Are they outdated or as per to western standards.
I will be really very very thankful if anyone of you can take just 5 minutes and somehow let me allay the fear of flying.
-Fatty
07-24-2008, 01:03 PM
#13
Gets Weekends Off
Joined APC: Jul 2008
Position: BE50C (A), BE95 (A), C172S (B)
Posts: 349
Sure you can fly an RNAV offset. It's typically illegal to do so in controlled airspace (Continental US talking here - your mileage in South America will vary) without permission from ATC or if you're over the ocean, and even those are conducted within known rules so that ATC knows where everyone is or will be.
IIRC, "primary radar" doesn't give you *ANY* altitude information whatsoever unless the aircraft in question is painted with a height-finder, which are typically only found attached to surface-to-air missile systems...Primary, at least I understand it, is bearing and distance only.
The primary cause of the Excel accident was a failure of Air Traffic Control to control traffic. Contributing factors were the failure of the pilots of both aircraft to maintain adequate vigilance to see and avoid other aircraft (a responsibility of each person operating an aircraft regardless of where they are although racing towards one another at >1000 knots I wonder what they really could've done), the Legacy's "inoperative" transponder/TCAS, and systemic defects in the Brazillian aviation system.
As I recall, the ATC responsible for the flights failed to note the Legacy's amended altitude on a flight strip, thereby not registering the fact that the airplanes were assigned to the same airway, at the same altitude, in opposite directions. Doesn't matter really whether the radar or transponders were working or not—even in a non-radar environment—ESPECIALLY in a non-radar environment, proper review and use of flight strips would have prevented this accident.
Primary radar in the United States is really good near the borders, as those are joint FAA/DOD sites used for interdicting smugglers, paid for by DOD, rather than by DOT.
Primary ARSR (Air Route Surveillance Radar, a center radar) might not be so hot in other places (ATL) comes to mind due to the equipment being 50s or 60s-era, but it works well enough when combined with operating Mode C transponders, required at and above 10,000 MSL, or within 30 nautical miles of major airports.
No information on what approach radars are like, but I suspect that they work pretty damned good, since they are necessarily installed at busy airports to keep airplanes from hitting one another.
IIRC, "primary radar" doesn't give you *ANY* altitude information whatsoever unless the aircraft in question is painted with a height-finder, which are typically only found attached to surface-to-air missile systems...Primary, at least I understand it, is bearing and distance only.
The primary cause of the Excel accident was a failure of Air Traffic Control to control traffic. Contributing factors were the failure of the pilots of both aircraft to maintain adequate vigilance to see and avoid other aircraft (a responsibility of each person operating an aircraft regardless of where they are although racing towards one another at >1000 knots I wonder what they really could've done), the Legacy's "inoperative" transponder/TCAS, and systemic defects in the Brazillian aviation system.
As I recall, the ATC responsible for the flights failed to note the Legacy's amended altitude on a flight strip, thereby not registering the fact that the airplanes were assigned to the same airway, at the same altitude, in opposite directions. Doesn't matter really whether the radar or transponders were working or not—even in a non-radar environment—ESPECIALLY in a non-radar environment, proper review and use of flight strips would have prevented this accident.
Primary radar in the United States is really good near the borders, as those are joint FAA/DOD sites used for interdicting smugglers, paid for by DOD, rather than by DOT.
Primary ARSR (Air Route Surveillance Radar, a center radar) might not be so hot in other places (ATL) comes to mind due to the equipment being 50s or 60s-era, but it works well enough when combined with operating Mode C transponders, required at and above 10,000 MSL, or within 30 nautical miles of major airports.
No information on what approach radars are like, but I suspect that they work pretty damned good, since they are necessarily installed at busy airports to keep airplanes from hitting one another.
07-24-2008, 03:25 PM
#14
Organizational Learning
Joined APC: Nov 2005
Position: Directly behind the combiner
Posts: 4,948
Contributing factors were the failure of the pilots of both aircraft to maintain adequate vigilance to see and avoid other aircraft (a responsibility of each person operating an aircraft regardless of where they are although racing towards one another at >1000 knots I wonder what they really could've done), ...
You suggested 1000 knots closure... use 900 for simpler math.
That's 15 nautical miles per minute.
That's a quarter of a mile per second.
How many seconds ahead can your eyes see? X?
(Remember, you'd be looking at that airplane from straight ahead, not from the side, or from above or below. It would first appear as just a dot.)
Do you scan straight ahead that frequently, every X seconds?
Food for thought.
.
07-24-2008, 04:45 PM
#15
Gets Weekends Off
Joined APC: Jul 2008
Position: BE50C (A), BE95 (A), C172S (B)
Posts: 349
You suggested 1000 knots closure... use 900 for simpler math.
That's 15 nautical miles per minute.
That's a quarter of a mile per second.
How many seconds ahead can your eyes see? X?
(Remember, you'd be looking at that airplane from straight ahead, not from the side, or from above or below. It would first appear as just a dot.)
.
That's 15 nautical miles per minute.
That's a quarter of a mile per second.
How many seconds ahead can your eyes see? X?
(Remember, you'd be looking at that airplane from straight ahead, not from the side, or from above or below. It would first appear as just a dot.)
.
07-24-2008, 09:44 PM
#16
Line Holder
Joined APC: Jun 2008
Position: Dozing for Dollars
Posts: 78
Why do you even have a profile on this forum? This forum is supposed to be for airline pilots. There are other forums on the net for you. I'm sorry you have a fear of flying. There are professionals who you can get to help you. We (the pilots) joined this site so we could discuss among flying professionals, not wanna-bes or the back-seaters. I'm sorry if my comments come off as rude and harsh -- just speaking my mind and opinion.
-Fatty
-Fatty
BTW does anyone know what the status of the Legacy crew is? I know they made it back to the US and did not go back to Brazil for the hearing. Can't say as I blame them.
gremlin
07-25-2008, 08:36 AM
#17
Gets Weekends Off
Joined APC: Aug 2006
Position: 737 Right
Posts: 1,385
Primary radar is never very accurate in altitude. Even on the border.
It's a design feature of surveillance radars. The radar has a "tall" beam that searches faster in azimuth but sacrifices vertical discrimination.
Phased arrays on the other hand...But I don't think any ATC radars use that technology. Military radars that use phased array can place an object pretty accurately in 3D.
It's a design feature of surveillance radars. The radar has a "tall" beam that searches faster in azimuth but sacrifices vertical discrimination.
Phased arrays on the other hand...But I don't think any ATC radars use that technology. Military radars that use phased array can place an object pretty accurately in 3D.
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